Glial Choristoma
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CT scan of extranasal glioma (midline, bottom of photo) *

Rare cases of lingual choristoma have been reported with glial tissue as the predominant or only tissue type present. This glial choristoma presents as a soft, painless, submucosal or deep nodule which is 1-2 cm. in diameter and is only slightly movable.  It has been reported in teenagers and young adults and may be an example of teratoma with glial predominance rather than true heterotopic brain tissue. The tumor is not associated with central nervous system pathosis or syndromes.

In the head and neck region, the most common sites of presentation are the cribriform area of the nasal sinus (nasal glioma) and the bridge of the nose (extranasal glioma), as seen in Figure 1.

Glial choristoma is comprised of an unencapsulated but fairly well demarcated submucosal aggregation of loose glial fibers intermixed with a variable number of mononuclear and multinucleated oval and stellate astrocytes with moderate eosinophilic cytoplasm (Figure 3). Ganglion cells may be numerous. Bands of fibrous tissue may be intermingled with the lesional cells or may surround clusters of cells. There is no evidence of cellular dysplasia or tissue necrosis.

Glial tissues with astrocytic differentiation are immunoreactive for glial fibrillary acidic protein (GFAP), S-100 protein and sometimes for vimentin. In general, the number of GFAP-positive cells is proportional to the degree of differentiation, and with glial choristoma there is enough cellular maturity to provide strong and diffuse reactivity. This reactivity will help to differentiate the lesion from neurilemoma, which lacks glial filaments, and from lingual metastasis of an anaplastic brain neoplasm.

Glial choristoma should be removed by conservative surgical excision.  No recurrence has been reported, nor has malignant transformation been reported.

Strome SE, McClatchey K, Kileny PR, Koopman CF. Neonatal choristoma of the tongue containing glial tissue - diagnosis and surgical considerations. Internat J Ped Otorhinolaryngol 1995; 33:265-273.

Ide F, Shimoyama T, Horie N. Glial choristoma in the oral cavity - histopathologic and immunohistochemical features. J Oral Pathol Med 1997; 26:147-150.